The present invention is generally related to methods, devices, and systems for controlling surgical fluid flows, often during treatment of an eye. In exemplary embodiments, the invention facilitates mounting of a cassette onto a surgical console so as to couple the console to a treatment probe, with the cassettes optionally comprising disposable structures having conduit networks for providing both irrigation and aspiration during treatments of anterior and/or posterior chambers of the eye, including phacoemulsification of cataracts, treatment of retinal diseases, and the like.
The optical elements of the eye include both a cornea (at the front of the eye) and a lens within the eye. The lens and cornea work together to focus light onto the retina at the back of the eye. The lens also changes in shape, adjusting the focus of the eye to vary between viewing near objects and far objects. The lens is found just behind the pupil and within a capsular bag, the capsular bag being a thin, relatively delicate structure which separates the eye into anterior and posterior chambers.
With age, clouding of the lens or cataracts are fairly common. Cataracts may form in the hard central nucleus of the lens, in the softer peripheral cortical portion of the lens, or at the back of the lens near the capsular bag. Cataracts can be treated by the replacement of the cloudy lens with an artificial lens. Phacoemulsification systems often use ultrasound energy to fragment the lens and aspirate the lens material from within the capsular bag. This may allow the capsular bag to be used for positioning of the artificial lens, and maintains the separation between the anterior portion of the eye and the vitreous humor in the posterior chamber of the eye.
During cataract surgery and other therapies of the eye, accurate control over the volume of fluid within the eye is highly beneficial. For example, while ultrasound energy breaks up the lens and allows it to be drawn into a treatment probe with an aspiration flow, a corresponding irrigation flow may be introduced into the eye so that the total volume of fluid in the eye does not change excessively. If the total volume of fluid in the eye is allowed to get too low at any time during the procedure, the eye may collapse and cause significant tissue damage. Similarly, excessive pressure within the eye may strain and injure tissues of the eye.
While a variety of specific fluid transport mechanisms have been used in phacoemulsification and other treatment systems for the eyes, aspiration flow systems can generally be classified in two categories: 1) volumetric-based aspiration flow systems using positive displacement pumps; and 2) vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface within a holding tank. Among positive displacement aspiration systems, peristaltic pumps (which use rotating rollers that press against a flexible tubing to induce flow) are commonly employed. Cassette systems can be used to couple peristaltic pump drive rotors or vacuum systems of the surgical consoles to an eye treatment handpiece, with the flow network conduit of the cassette being disposable to avoid cross-contamination between different patients.
To provide surgeons with the benefits of vacuum-based and/or displacement-based aspiration flows as appropriate for a particular procedure or portion of a procedure, it may be desirable to include both peristaltic pump drive components and a vacuum system in a single eye treatment console. Unfortunately, as eye treatment consoles get more complex, the challenge of accurately and quickly coupling a probe and appropriate cassette to an eye surgery console may increase significantly. Increased difficulties and challenges in accurately and appropriately preparing an eye treatment system for treatment of a particular patient may decrease the number of patients who will benefit from treatments from each system, and might also increase the possibility of errors or injury to a patient.
In light of the above, it would be advantageous to provide improved devices, systems, and methods for eye surgery. It would be particularly advantageous if these improvements allowed system users to configure an eye treatment system quickly, accurately, and securely, without requiring the surgical staff to manually apply excessive force and without subjecting the various interfacing components to unnecessary strains, torques, or the like. It would be particularly advantageous if mounting of a cassette onto a console could be performed easily and securely while the cassette is supported by a single hand.